Polarized relay



Feb. 2, 1943. J. s. GARVIN 2,309,945

"POLARIZED RELAY Filea July 11, 1940 2 2 0 [1 I F/G/ v FIG.)

/7 :2 /7 i Q) I7 I 2 3 20 I IO INVENTOR J. S. GARV/N By flaw I ATTORNEYPatented Feb. 2, 1943 UNITED STATES PATENT OFFlCE POLARIZED RELAYApplication July 11, 1940, Serial No. 344,902

Claims.

This invention relates to an electromagnetic device and moreparticularly to a polarized relay.

It is often desirable in signalling systems to selectively close twowork circuits by the operation of a polarized relay in response to theenergization of its winding by current of either positive or negativepotential. If a polarized relay of the type which has a single armaturebiased to a neutral position is used for this type of service, there isalways the possibility that if the armature is not accurately biased inits neutral position, it may fail to operate on current of one polarityor may operate falsely due to vibration when its winding is notenergized or is energized by current of a non-operating value.

It is therefore the object of the present invention to provide a relaystructure of the polarized type which has three very definite positionsof which two are circuit closing and the third a neutral or open circuitposition.

It is a further object of the invention to provide a polarized relaystructure which has a suitable margin of safety against false operationwhen a high percentage of the operate current is flowing and the deviceis at the same time subject to vibration.

It is a further object of the invention to provide a polarized relaystructure which is economical to manufacture and which requires aminimum of maintenance.

In accordance with this invention, these objects are attained byassembling two neutral relays of a well-known commercial type side byside and interconnecting their cores at their heel-piece ends by a stripof magnetic material and interconnecting their cores at their forwardends by a polarizing magnet. The windings of the two relays may beeither connected in series or in parallel in such a manner as tomagnetize the two cores in the same sense.

For a more comprehensive understanding of the invention reference may behad to the following detailed description taken in connection with theaccompanying drawing in which:

Fig. 1 is a top plan view of the relay assembly;

4 shows the magnetic circuit elements of' of other types could equallywell be employed in the assembly or the assembly could be designed denovo to incorporate the features of the invention.

Each relay unit comprises a core the rear end of which is widened toform a heel-piece 2 and is bifurcated to form two sections bent inopposite directions to provide mounting ears 3 and 4 by which the relayunit may be attached to a mounting plate and the forward end of whichcore is provided with a pole-face 5. Mounted on the core I is anenergizing winding 6 having a rear spoolhead and a forward spoolhead 8.The U- shaped armature 9 is positioned with its forward cross-reach I0overlying the pole-face 5 of the core and its side arms extending oneither side of the winding 6 with their ends pivoted to the forward edgeof the heel-piece 2 by reed springs The cross-reach ID of the armatureis normally biased against the back-stop nut l2 which is threaded uponone end of stud l3 secured in a hole in the end of the core I. Theback-stop nut l2 serves as a means for limiting the releasing movementof the armature and for adjusting the Width of the air-gap between thecross-reach H] of the armature and the pole-face 5 of the core I.

For biasing the armature against the back-stop nut, a balancing springI4 is provided, the forward or free end of which engages an insulatingstud i5 secured to the forward end of the armature and the rear end ofwhich is secured to one end of the heel-piece 2 by screws it. Alsosecured to the same end of the heel-piece 2 by the screws I6 is awinding terminal lug H. The screws |G extend through holes in an outerclamping plate l8, terminal lug ll, insulating strips which insulate thelug from the plate is and from the heel-piece 2, through holes in theheel-piece, spacers and spring I4 into threaded holes in the innerclamping plate l8.

Insulatedly mounted on the other end of the heel-piece 2 are a secondwinding terminal lug 22 and a pair of contact springs 2| and 22 whichare secured to the heel-piece by the screws 23, outer clamping plate 24and inner clamping plate 25. The free ends of contact springs 2| and 22eX- tend forwardly beneath a side-arm of the armature, the end of spring2| engaging against an insulating stud 26 secured to the forward end ofthe armature. Spring 2| thus assists balancing spring I4 in normallybiasing the armature against the back-stop nut l2 in which position thecontacts carried by the springs 2| and 22 are out of engagement. Fordetermining the normal gap between the contacts of springs 2| and 22,the spring 22 is provided with a bendable tang 21 which engages ashoulder on the edge of th front spoolhead 8.

Also secured to the outer face of the heel-piece 2 by the screw 28 is acover guide 29. This guide is substantially rectangular in shape havingsidearms which serve to guide a can cover 40 into position, a centralspring arm 30 having the end thereof formed for engagement in adepression in a wall of the can cover to retain the cover upon the coverguide and with two fingers 3| which engage in notches in the edge of thefront spool.- head 8 and which with the screw 28 hold the guide in itsproper position. The cover 40, which also serves as a shield for therelay, is indicated in dotted lines as positioned on the cover guides 29of the assembled relay. The front. closure-39. of the cover is shown infull lines as removed from the'forward end of the cover 40 and is;provided with a spring actuating stud 38 secured. thereto. for a purposeto be later described.

One of? the relay units is also provided with a pair of springs 35 and3'!- insulated from each other and clamped with the balancing, spring I4to the heel-piece 2' by the clamping plates I8 and t9 and'the screws I6.Spring. 35 is rovided with a cam surface 36- on its outer end forengagement by the actuating: stud 38' secured to the can cover closure39 whereby when the can cover 40 is positioned on the cover guides 29and the closure 39 is in position in the forward end of the" can coverthe stud 38 will cause the spring 35 to be: cammed into engagement withspring 3-1. The springs 35 and 31 may be connected in series with onespring of each. pair 2 I, 22 so thatwhen the: can, cover and closure:are inplace. thesprings 35 and 31 will be closedto render the workcircuits of the relay effective but that when either the can cover orthe closure is removed the, springs will be: open; to render the-workcircuits ineffective. It is thus possible to. remove; the can cover, orthe front: closure thereof and. to adjust the pairs of springs 21-, 22without falselyclosing. the: work.v circuits controlled bysuch pairs ofsprings.

The two relay units are secured together side by sidezas most clearlydisclosed in- Figs. 1 and 2 by a U-shaped strip 32" of magnetic materialand a u-shaped permanent magnet 33. The strip 32 is secured between theheel-pieces 2 by" the screws 28- which extend through holes in theheel-pieces into threaded holes in the arms of thestrip 3 2-. The armsof the permanent magnet 33 are provided with slots through which theinner ends of the studs I3 extend, the arms being clamped to the ends ofthe cores. I by the nuts 34 threaded upon studs.

The windings 6- of the two relayunits maybe connected in series or inparallel in such a manner that when they are energized, they will causeflux'to flow-in thesame direction in both cores I.

Referring to Fig. 4-; it will be noted that there is normally a closedmagnetic circuit extending through the permanent magnet 33, the twocores I and the strip 32 and thatwith the magnet 33 polarized asindicated-,- the. pole-face on. the right-hand core I is made a northpole and the pole-face-of the left-hand core I is made a south pole.Because of the-low reluctance of the closed magnetic circuit through'themagnet 33, there will be little, if any, fiuxflowing in the openmagnetic, circuitextending from the north pole of magnet: 33', acrossthe right-hand air-gap through the right-hand armature 3-, the strip 32;the left-hand armature 9 and the left-hand air-gap to the south pole ofmagnet 33 and consequently both armatures will be held against theirback-stop nuts I2 by their associated springs I l and 2I and thecontacts between the two pairs of springs 2I and 22 will be maintainedopen as shown in Fig. 1.

If it now be assumed that current is directed through the windings 6 insuch a direction as to establish a flow of flux through the two cores Iin such a direction as to make the forward ends of both coreselectromagnetic north poles and the rear ends of both cores south poles,then the forward ends of both armatures will become south poles. Thepole-face 5 of the right-hand core I now becomes more strongly a northpole and since the end of the right-hand armature is. made a south pole,a substantial difference of magnetic potential is established across theright-hand air-gap and flux will flow forwardly through the right-handcore I across the righthand air-gap and back through the right-handarmature and flux will also flow forwardly in the left-hand core Ithrough the magnet 33 across the right-hand air-gap back through therighthand armature 3 and strip 32, of sufiicient strength. to cause theattraction of the righthand' armature and the closure of its associatedcontact springs 2I and 22. Since, however, the pole-face dot theleft-hand core has been made a north pole in opposition to the polarityimpressed thereon by the magnet 33, the difference in magnetic potentialbetween this pole-face and the end of the left-hand armature is slight,little flux flows across the left-hand air-gap, and the left-handarmature is therefore not attracted.

If current is directed in the opposite direction through the windings 5,then a flow, of flux will be established through the two cores I insuch, a direction as to make the forward ends of both coreselectromagnetic south poles and the forward ends of both arniaturesnorth poles. The pole-face E of the left-hand core I nowbecomes morestrongly a south pole and since the end of the left-hand armature ismade a north pole a substantial clifierence of magnetic potential isestablished across the left-hand air-gap and flux will flow rearwardlythrough the lefthand core I, forwardly'through the left-hand or. matureand across the left-hand air-gap. and flux will also flow rearwardlythrough the righthand core I through. the strip 32, thence forwardlythrough the left-hand armature and across the left-hand air-gap andthrough the magnet 33 to cause the attraction of the left-hand armatureand the closure of its associated contact springs Ill and 22. Since,however, the pole-face 5 of the right-hand core has been made a southpole in opposition to the polarity impressed therein by the magnet 3-3,the difference-in magnetic potential between this pole-face and the endof the right-hand armature is slight, little f ux flows across the righthand air-gap, and the right-hand armature is therefore not attracted.

While a permanent magnet 33 has been disclosed as interconnecting theforward ends of the cores i it will be apparent that the samepolarizing. efiect could be secured by connecting the forward ends ofthe cores by a bar of magnetic material ener ized by a polarizingwinding.

From the foregoing it will be apparent that a polarized relay structureis provided which-is inexpensive to: manufacture, since in the mainstandard relay parts are employed, and. which provides for very definiteand, dcsirablethreeposition operation.

What is claimed is:

1. In a polarized relay, two cores, each having an energizing windingthereon, mean for magnetically interconnecting one end of one core toone end of the other core, a polarizing magnet interconnecting the otherends of said cores, said cores, interconnecting means and magnetconstituting a closed magnetic circuit and two armatures pivotallysupported one on each of said cores and forming normally open magneticcircuits therewith, said armatures alternatively attractable to theirrespective cores in accordance with the direction of current fiowthrough said energizing windings.

2. In a polarized relay, two cores, each having an energizing windingthereon, means for magnetically interconnecting one end of one core toone end of the other core, a permanent magnet interconnecting the otherends of said cores, said cores, means and magnet constituting a closedmagnetic circuit, and two armatures pivotally supported one on each ofsaid cores and forming normally open magnetic circuits therewith, saidarmatures alternatively attractable to their respective cores inaccordance with the direction of current flow through said energizingwindings.

3. In a polarized relay, two parallelly disposed cores each having anenergizing winding thereon, a permanent magnet interconnecting theforward ends of said cores, a yoke of magnetic material for connectingthe rear ends of said cores, said cores, yokes and magnet constituting aclosed magnetic circuit and two armatures pivotally supported one oneach of said cores and forming normally open magnetic circuitstherewith, said armatures alternatively attractable to their respectivecores in accordance with the direction of current flow through saidenergizing windings.

4. In a polarized relay, two parallelly disposed cores each having anenergizing winding thereon, a U-shaped permanent magnet disposed betweenthe forward ends of said cores, a U-shaped yoke of magnetic materialdisposed between the rear ends of said cores, screws extending throughholes in said cores and in the arms of said yoke for securing the yoketo said cores, a back-stop stud threaded through the forward end of eachcore and extending through a hole in an arm of said magnet, nuts on saidstuds for clamping the arms of said magnet to the forward ends of saidcores, two armatures cooperative respectively with said cores andback-stop nuts on said studs for adjusting the air-gaps between saidcores and said armatures.

5. In a polarized relay, two parallelly disposed cores, each having anenergizing winding thereon, a U-shaped permanent magnet disposed betweenthe forward ends of said cores, a U-shaped yoke of magnetic materialdisposed between the rear ends of said cores, screws extending throughholes in said cores and in the arms of said yoke for securing the yoketo said cores, a back-stop stud threaded through the forward end of eachcore and extending through a hole in an arm of said magnet, nuts on saidstuds for clamping the arms of said magnet to the forward ends of saidcores, two armatures cooperative respectively with said cores, back-stopnuts on said studs for adjusting the air-gaps between said cores andsaid armatures and biasing springs for normally holding said armaturesin their retracted positions against said back-stop nuts.

JOHN S. GARVIN.

